1. Technical Field
The present invention relates to a coaxial connector connecting structure connecting a coaxial connector provided on a housing of a high-frequency circuit and a high-frequency circuit module case accommodated in the housing, and a high frequency device equipped with the coaxial connector connecting structure.
2. Background Art
A high-frequency device such as wireless transmitter and receiver, a radio transmitter, a radio receiver and a linear amplifier is provided with a coaxial structural section of a high-frequency circuit which treats a high-frequency signal such as microwave. Such a coaxial structural section may have to perform plating treatment to an inner wall around a central conductor in order to secure a high signal characteristic by reducing loss due to a skin effect.
However, owing to the nature of the plating treatment, unnecessary plating is inevitable for the entire region composing the space of the coaxial structural member and thereby increasing the cost of the plating treatment. When a high frequency circuit is used in outdoor equipment, waterproof treatment is needed so that water does not enter its interior so as not to generate corrosion caused by water such as rainwater adhered to an electric potential difference part between the plating material and the other metal contacted thereto.
In order to solve the above-mentioned problem, the plating treatment area should be made minimal while the structure excellent in signal characteristic should be realized.
Technological examples related to connecting structure of a high-frequency circuit are disclosed in following patent documents 1-6.
The patent document 1 (Japanese Utility Model Registered No. 2561038) discloses a high-frequency signal connecting unit where a coaxial connector provided on a box-shaped metal case is designed to have a tapered outer surface of a sleeve structure. One end of this sleeve is arranged to pass through a side of the metal case and fixed to the metal case by using a nut located in the case. The other side of this sleeve is fitted in between an insulator and an outer conductor of a coaxial cable. Accordingly, a central conductor of the coaxial cable is arranged such that, at the outside of the metal case, it is completely covered with the sleeve which entirely touched with the outer conductor, and in the inside of the metal case, the central conductor is completely covered with the metal case.
In the patent document 2 (Japanese Utility Model Application Laid-Open No. SHO-59(1984)-041980), a connecting structure between two high-frequency circuit chassis is disclosed where a connecting tool of a thick cylindrical conductor is inserted in a connecting location between opposing side walls of two chassis and being fixed to the chassis by using nuts, respectively. Each wall attached with the connecting tool is provided with a hole having a diameter which is equal to the inside diameter of the connecting tool internal space or rather somewhat larger than that, and an insulated wire is fitted through the internal space of the connecting tool such that the insulated wire has a central conductor of a diameter by which the characteristic impedance would be Z0.
The patent document 3 (Japanese Utility Model Application Laid-Open No. HEI-06(1998)-048920) discloses a fixing structure for electronic parts or the like in which the electronic part or the like is inserted into an attachment hole provided in a metal casing and being fixed by soldering. The metal casing is fabricated by using a metal plate which is performed plating processing on its surface. An inserting portion of the electronic part or the like is inserted into the attachment hole such that the insetting portion is elastically supported by a contact arm. Then the insert portion is fixed to the metal casing by using a solder.
The patent document 4 (Japanese Patent Application Laid-Open No. 2000-059140) discloses a high frequency transmitting/receiving device in which an antenna board and a transmitting/receiving circuit board are provided on a front surface and back surface of a base plate, respectively, and they are connected each other by using a coaxial line which penetrates the base plate.
Since the antenna and transmitting/receiving circuit is separated by the base plate, workability of the entire assembling process is improved when the area of the transmitting/receiving circuit is small enough compared with the area of the antenna.
The patent document 5 (Japanese Patent Application Laid-Open No. HEI-02(1990)-135901) discloses a mounting structure of an electronic part for microwave circuits.
An external connection pin of the electronic part is used as an inner conductor while a metallic chassis and a conductor plating part of a through hole are used as an outer conductor so as to form a coaxial line. Thus the electronic part is connected to an external connection member through this coaxial line.
The patent document 6 (Japanese Patent Application Laid-Open No. HEI-04(1992)-069913) discloses a feed through capacitor in which a synthetic resin coated with a metallic film is used for an outer casing electrode and a penetration electrode.
Because of such structure, elastic modulus and coefficient of linear expansion of those electrodes are almost equal to that of complex dielectrics filled in the outer casing electrode, and thus not causing a gap between the complex dielectrics and the two electrodes even in a thermal stress at the time of a temperature cycle of the hot and cold. Moreover, it is disclosed that a decline of the capacitance does not occur and crack occurrence of complex dielectrics can also be prevented.